Compared with liquid crystal displays (LCDs), organic light emitting diode (OLED) devices have the advantages such as self light-emitting, fast response, wide viewing angle, high brightness, colorful color, thin profile and so on, and the organic light emitting diode (OLED) devices are considered as the next generation of display technology.
The film forming methods for OLED mainly include an evaporation process and a solution process. The evaporation process is more mature in small size application, at present, the technology has been applied in mass production. In the solution process, the OLED film formation methods mainly are ink jet printing, nozzle coating, spin coating, silk screen printing, etc, wherein the inkjet printing technology is considered to be an important way for mass production of large size OLED because of its high material utilization ratio and capable of realizing large size production.